CN110268637B

CN110268637B - User equipment and method for SRS transmission

Info

Publication number: CN110268637B
Application number: CN201880010211.XA
Authority: CN
Inventors: 柿岛佑一; 大泽良介; 武田和晃; 永田聪
Original assignee: NTT Docomo Inc
Current assignee: NTT Docomo Inc
Priority date: 2017-02-03
Filing date: 2018-02-02
Publication date: 2022-07-19
Anticipated expiration: 2038-02-02
Also published as: US20190379502A1; US11121837B2; CN110268637A; WO2018144916A1; JP2020507991A; EP3577838A1

Abstract

Disclosed is a User Equipment (UE) including a receiver that receives Sounding Reference Symbol (SRS) setting information indicating a first resource for transmitting a predetermined reference signal from a Base Station (BS). The UE includes a transmitter that transmits the SRS using a second resource that is the first resource. The UE also includes a processor that determines a precoder applied to the SRS based on a predetermined reference signal. The transmitter transmits the SRS precoded using the determined precoder. The predetermined reference signal is a channel state information reference signal (CSI-RS), an SRS, or a Synchronization Signal Block (SSB)/a Physical Broadcast Channel (PBCH).

Description

User equipment and method for SRS transmission

Technical Field

The present invention relates generally to a User Equipment (UE) and method for Sounding Reference Signal (SRS) transmission.

Background

In a wireless communication system, a Sounding Reference Signal (SRS) is used to estimate an uplink channel state of a Base Station (BS). Conventional Long Term Evolution (LTE) standards (e.g., release 13(rel.13) LTE) do not explicitly support a beamformed SRS scheme to apply beamforming to SRS for uplink channel conditions.

On the other hand, a New Radio (NR) (fifth generation (5G)) access technology may apply a beamforming technique to SRS to ensure coverage for SRS transmission, reduce the number of Antenna Ports (APs) for SRS transmission and Reference Signals (RSs), and determine uplink beams (e.g., beam scanning using SRS). In order to apply beamforming to SRS, appropriate physical signals need to be specified. For example, the selection of SRS beams may depend on the RS state.

[ citation list ]

[ non-patent citation ]

[ non-patent document 1]3GPP, TS 36.211V 14.1.0

[ non-patent document 2]3GPP, TS 36.213V14.1.0

Disclosure of Invention

One or more embodiments of the present invention relate to a User Equipment (UE) including a receiver that receives Sounding Reference Symbol (SRS) setting information indicating a first resource for transmitting a predetermined reference signal from a Base Station (BS). The UE includes a transmitter that transmits the SRS using a second resource that is the first resource.

One or more embodiments of the present invention relate to a method of Sounding Reference Symbol (SRS) transmission in a wireless communication system, the method including: receiving, using a User Equipment (UE), SRS setting information indicating a first resource for transmitting a predetermined reference signal from a Base Station (BS); and transmitting the SRS from the UE to the BS using the second resource as the first resource.

Drawings

Fig. 1 is a diagram illustrating a setup of a wireless communication system according to one or more embodiments of the present invention.

Fig. 2 is a sequence diagram illustrating an example of an operation of a beam selection scheme for SRS transmission according to one or more embodiments of the first example of the present invention.

Fig. 3 is a diagram illustrating the setting of SRS setting information according to one or more embodiments of the first example of the present invention.

Fig. 4 is a sequence diagram showing an example of an operation of SRS transmission according to one or more embodiments of the first modified example of the present invention.

Fig. 5 is a diagram illustrating setting of CSI setting information according to one or more embodiments of a first example of the present invention.

Fig. 6 is a diagram illustrating a schematic setup of a BS according to one or more embodiments of the present invention.

Fig. 7 is a diagram illustrating a schematic setup of a UE according to one or more embodiments of the present invention.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the embodiments of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid obscuring the invention.

In one or more embodiments of the invention, a beam may be referred to as a resource or a radio resource.

Fig. 1 is a wireless communication system 1 in accordance with one or more embodiments of the present invention. The wireless communication system 1 includes a User Equipment (UE)10 and a Base Station (BS) 20. The wireless communication system 1 may be a New Radio (NR) system. The wireless communication system 1 is not limited to the specific settings described herein and may be any type of wireless communication system, such as an LTE/LTE-advanced (LTE-a) system.

The BS 20 may communicate Uplink (UL) signals and Downlink (DL) signals with the UE10 within a cell of the BS 20. The DL signal and the UL signal may include control information and user data. The BS 20 may be a new generation nodeb (gnb).

The BS 20 includes an antenna, a communication interface (e.g., X2 interface) for communicating with the neighboring BS 20, a communication interface (e.g., S1 interface) for communicating with a core network, and a CPU (central processing unit), such as a processor or a circuit for processing signals transmitted and received with the UE 10. The operations of the BS 20 may be implemented by a processor processing or executing data and programs stored in a memory. However, the BS 20 is not limited to the above-described hardware configuration, and may be implemented by other suitable hardware configurations as understood by those of ordinary skill in the art. A plurality of BSs 20 may be arranged to cover a wider service area of the wireless communication system 1.

The UE10 may communicate DL signals and UL signals including control information and user data with the BS 20 using Multiple Input Multiple Output (MIMO) technology. The UE10 may be a mobile station, a smartphone, a cellular phone, a tablet, a mobile router, or an information processing device with radio communication functionality, such as a wearable device. The wireless communication system 1 may include one or more UEs 10.

The UE10 includes a CPU such as a processor, a RAM (random access memory), a flash memory, and a radio communication device to transmit and receive radio signals to and from the BS 20 and the UE 10. For example, the operations of the UE10 described below may be implemented by the CPU processing or executing data and programs stored in the memory. However, the UE10 is not limited to the above-described hardware setting, and may also be set with, for example, a circuit to implement the processing described below.

(first example)

The following will describe in detail an embodiment of the first example of the present invention.

In one or more embodiments of the present invention, as shown in fig. 1, the BS 20 may transmit SRS setting information in step S1.

The SRS setting information indicates setting of a relationship between a Reference Signal (RS) (predetermined RS) and an SRS to be transmitted. The RS may be a channel state information reference signal (CSI-RS), a Synchronization Signal Block (SSB)/Physical Broadcast Channel (PBCH), a downlink demodulation reference signal (DM-RS), an uplink DM-RS, or an RS in the same link, such as an SRS. For example, the SRS setting information indicates that a beam for RS transmission is selected as a beam for SRS transmission. For example, the SRS setting information indicates RSs used to determine a beamforming vector of the SRS. For example, the beam may be determined based on reciprocity (reciprocity) of the wireless channel.

When the UE10 receives the SRS setting information, the UE10 may select a beam for Sounding Reference Signal (SRS) transmission based on the SRS setting information. At step S2, the UE10 may transmit the SRS to the BS 20 using the selected beam.

According to one or more embodiments of the first example of the present invention, it is possible to specify an RS for beam selection for SRS transmission by using an SRS transmission framework.

Fig. 2 is a sequence diagram illustrating an example operation of a beam selection scheme according to one or more embodiments of the first example of the invention.

As shown in fig. 2, the BS 20 may transmit SRS setting information and then the UE10 may receive the SRS setting information in step S11. The SRS setting information may be transmitted from the BS 20 to the UE10 through higher layer signaling such as radio resource control signaling. The SRS setting information is newly designed information for specifying an RS used for beam selection for SRS transmission. The SRS setting information may indicate a beam for transmitting the RS.

In step S12, the UE10 may select a beam for transmitting the SRS based on the SRS setting information. For example, the UE10 may select a beam for transmitting the RS as a beam for SRS transmission. For example, in the SRS setting information, CSI-RS, SSB/PBCH, SRS, or uplink/downlink DM-RS may be specified.

In step S13, the UE10 may transmit the SRS using the selected beam.

For example, the UE10 determines a precoder applied to the SRS to be transmitted based on the RS. At step S13, the UE10 may transmit an SRS precoded with the determined precoder.

As shown in fig. 3, the SRS setting information may include "resource setting", "RS specification information for beam selection of SRS", and "link" information. The resource setting (M > -1) includes RS information for signal quality measurement and IMR information for interference measurement. For example, in the RS information, an RS type, the number of APs for RS transmission, and a time/frequency reuse location may be specified.

Therefore, according to one or more embodiments of the first example of the present invention, it is possible to specify an RS for beam selection for SRS transmission and a beam for transmitting the RS by using an SRS transmission framework. Accordingly, a beam for SRS transmission may be determined based on the SRS transmission.

(first modified example)

In one or more embodiments of the first modified example of the present invention, a beam for SRS transmission may be determined based on channel information derived from CSI-RS (having channel reciprocity). Fig. 4 is a sequence diagram illustrating an example operation of SRS transmission according to one or more embodiments of the first modified example of the present invention.

As shown in fig. 4, the BS 20 may transmit SRS setting information to the UE10 at step S21.

In step S22, the BS 20 may transmit CSI-RS setting information to the UE 10. The setting of the CSI-RS setting information will be described with reference to fig. 5. Then, the BS 20 may transmit the CSI-RS, which may be transmitted to the UE10 using the beam, at step S23.

At step S24, the UE10 may transmit the SRS based on the reception of the CSI-RS. The SRS may be precoded using beams for CSI-RS reception. The same beamforming may be applied to all SRS APs. As another example, different beamforming may be applied to the SRS AP, e.g., based on multiple RSs used as references for SRS beamforming.

As shown in fig. 5, the CSI setting information includes "resource setting", "CSI report setting", and "link" information.

The resource setting (M > ═ 1) includes RS information for signal quality measurement and Interference Measurement Resource (IMR) information for interference measurement. For example, in the RS information, an RS type, the number of APs for RS transmission, and a time/frequency reuse location may be specified. In the IMR information, a time/frequency reuse position of the IMR may be specified.

The CSI report setting (N > ═ 1) includes CSI report timing information, a CSI calculation method, and on/off information of a feedback Rank Indicator (RI), a Precoding Matrix Indicator (PMI), a CSI-RS resource indicator (CRI), and a Channel Quality Indicator (CQI). For example, in CSI reporting timing information, "periodic", "aperiodic", or "semi-persistent" may be specified. For example, the CSI calculation method may be a measurement limit.

Link (L > ═ 1) indicates a combination of resource setting and CSI report setting. In the example of fig. 5, four RSs corresponding to links #0, #1, #2, and #3 are used for CSI estimation.

According to one or more embodiments of the first modified example of the present invention, as shown in fig. 5, the CSI report setting includes information for SRS transmission. For example, the SRS is transmitted instead of the CSI report. The UE10 may determine a beam for SRS based on the reception quality of the RS indicated in the resource setting associated with the CSI report setting.

Further, according to one or more embodiments of the first modified example of the present invention, the CSI setting information may include SRS transmission information. The SRS transmission information is information for normally transmitting the SRS. For example, the SRS transmission information may include at least one of the number of APs used for SRS transmission, transmission timing, frequency information, and combination (comb) information. The SRS transmission information may be associated with a setting of SRS transmission and may be designated as an SRS resource index.

Therefore, according to one or more embodiments of the first modified example of the present invention, it is possible to specify an RS for beam selection for SRS transmission and a beam for transmitting the RS by using a CSI acquisition framework. Accordingly, a beam for SRS transmission may be determined based on the CSI setting information.

(Another example of the first example)

As another example of the first example, when the RS is set with a plurality of APs, a beam for SRS transmission may be determined using a part of the plurality of APs, for example. For example, the beam for SRS may be the beam associated with the AP whose AP number is the smallest. Also, for example, the beam used for SRS transmission may be a beam associated with an AP whose AP number is designated by the base station 20 (gNB).

(second example)

A second exemplary embodiment of the present invention will be described in detail below. According to one or more embodiments of the second example of the present invention, the SRS transmission timing may be determined based on the trigger timing of the RS.

Further, according to one or more embodiments of the second example of the present invention, the SRS transmission timing may be determined based on the reception timing of the RS.

For example, according to one or more embodiments of the second example of the present invention, the SRS may be multiplexed within a subframe of the RS (self-contained frame setting).

For example, the SRS may be transmitted on a predetermined subframe from when the UE10 receives the CSI-RS. The predetermined time interval may be a constant value defined by a specification or may be set.

(third example)

When the precoding matrix of the SRS has flexibility, beam management of the BS 20 may be complicated. For example, when the uplink beam has large flexibility, controlling uplink quasi-co-location (QCL) information at the BS 20 may be very difficult.

According to one or more embodiments of the third example of the present invention, a precoding vector that can be applied to the SRS may be limited. For example, the precoding vector may be selected from a predetermined codebook (e.g., a rank 1 codebook). In addition, the BS 20 may notify the UE10 of the applied codebook. The restriction may be applied to a limited frequency band, e.g., a sub-band, and/or a limited duration, e.g., a sub-frame. For example, the UE10 may be allowed to change beams in a limited timing. For example, the UE10 may be allowed to change beams every 10 ms.

According to one or more embodiments of the third example of the present invention, the BS 20 may be notified of precoding information applied to the SRS. For example, how the UE10 uses the beam as the PMI or QCL information may be notified.

According to one or more embodiments of the third example of the present invention, precoding information applied to a Physical Uplink Shared Channel (PUSCH) is transmitted to an SRS together with notification of QCL information.

According to one or more embodiments of the third example of the present invention, the antenna panel(s) (or antennas) used for SRS transmission may be restricted. The restriction may be applied to a limited frequency band, e.g., a sub-band, and/or a limited duration, e.g., a sub-frame. For example, the UE may be allowed to change the antenna panel(s) in limited timing. For example, the UE is allowed to change the antenna panel (or panels) every 10 ms.

Also, the technology according to one or more embodiments of the third example of the present invention may be applied to an uplink RS and an uplink physical channel.

(setting of base station)

The BS 20 according to one or more embodiments of the present invention will be described below with reference to fig. 6. Fig. 6 is a diagram illustrating a schematic setup of the BS 20 according to one or more embodiments of the present invention. The BS 20 may include a plurality of antennas (antenna element group) 201, an amplifier 202, a transceiver (transmitter/receiver) 203, a baseband signal processor 204, a call processor 205, and a transmission path interface 206.

User data transmitted on the DL from the BS 20 to the UE 20 is input from the core network 30 to the baseband signal processor 204 through the transmission path interface 206.

In the baseband signal processor 204, the signal is subjected to Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer transmission processing such as segmentation and coupling of user data, and RLC retransmission control transmission processing, Medium Access Control (MAC) retransmission control including, for example, HARQ transmission processing, scheduling, transport format selection, channel coding, Inverse Fast Fourier Transform (IFFT) processing, and precoding processing. The resulting signal is then transmitted to each transceiver 203. For the signal of the DL control channel, transmission processing including channel coding and inverse fast fourier transform is performed, and the resultant signal is transmitted to each transceiver 203.

The baseband signal processor 204 notifies each UE10 of control information (system information) for communication in the cell through higher layer signaling (e.g., RRC signaling and broadcast channel). The information used for communication in a cell includes, for example, UL or DL system bandwidth.

In each transceiver 203, the baseband signal which is precoded per antenna and output from the baseband signal processor 204 is subjected to frequency conversion processing to enter a radio frequency band. The amplifier 202 amplifies the frequency-converted radio frequency signal, and the resultant signal is transmitted from the antenna 201.

For data to be transmitted from the UE10 to the BS 20 on the UL, a radio frequency signal is received in each antenna 201, amplified in an amplifier 202, subjected to frequency conversion in a transceiver 203 and converted into a baseband signal, and then input to a baseband signal processor 204.

The baseband signal processor 204 performs FFT processing, IDFT processing, error correction decoding, MAC retransmission control reception processing, and RLC layer and PDCP layer reception processing on user data contained in the received baseband signal. The resulting signal is then transferred to the core network 30 through the transmission path interface 206. The call processor 205 performs call processing such as setting up and releasing a communication channel, managing the state of the BS 20, and managing radio resources.

(setting of user Equipment)

The UE10 according to one or more embodiments of the present invention will be described below with reference to fig. 7. Fig. 7 is a schematic set-up of a UE10 according to one or more embodiments of the present invention. The UE10 has a plurality of UE antennas 101, an amplifier 102, circuitry 103 including a transceiver (transmitter/receiver) 1031, a controller 104, and applications 105.

For DL, radio frequency signals received in the UE antennas 101 are amplified in respective amplifiers 102 and undergo frequency conversion to baseband signals in the transceivers 1031. These baseband signals undergo reception processing such as FFT processing, error correction decoding, retransmission control, and the like in the controller 104. The DL user data is transferred to the application 105. The application 105 performs processing related to a physical layer and a higher layer above the MAC layer. In the downlink data, broadcast information is also transmitted to the application 105.

On the other hand, UL user data is input from the application 105 to the controller 104. In the controller 104, retransmission control (hybrid ARQ) transmission processing, channel coding, precoding, DFT processing, IFFT processing, and the like are performed, and the resulting signal is transmitted to each transceiver 1031. In the transceiver 1031, the baseband signal output from the controller 104 is converted into a radio frequency band. The frequency-converted radio frequency signal is then amplified in an amplifier 102 and then transmitted from the antenna 101.

(Another example)

One or more embodiments of the present invention may be used independently for each of the uplink and downlink. One or more embodiments of the present invention may also be used in common for both the uplink and downlink.

Although the present disclosure mainly describes examples of NR-based channels and signaling schemes, the present invention is not limited thereto. One or more embodiments of the present invention can be applied to another channel and signaling scheme having the same function as LTE/LTE-a and a newly defined channel and signaling scheme.

Although the present disclosure mainly describes examples of a CSI-RS and SRS-based channel estimation and CSI feedback scheme, the present invention is not limited thereto. One or more embodiments of the present invention may be applied to another synchronization signal, reference signal, and physical channel, such as CSI-RS, Synchronization Signal (SS), measurement RS (mrs), mobility RS (mrs), and beam RS (brs). For example, beamforming of PUSCH and/or uplink DM-RS may be determined with a related RS (e.g., CSI-RS). For example, beamforming of PDSCH and/or downlink DM-RS may be determined with the associated RS (e.g., SRS). For example, beamforming of the CSI-RS may be determined with a related RS (e.g., SRS).

Although this disclosure primarily describes examples of various signaling methods, signaling in accordance with one or more embodiments of the present invention may be performed explicitly or implicitly.

Although the present disclosure primarily describes examples of various signaling methods, signaling according to one or more embodiments of the present invention may be higher layer signaling, such as RRC signaling, and/or lower layer signaling, such as Downlink Control Information (DCI) and MAC Control Element (CE). Furthermore, signaling in accordance with one or more embodiments of the present invention may use Master Information Blocks (MIBs) and/or System Information Blocks (SIBs). For example, according to one or more embodiments of the present invention, at least two of RRC, DCI, and MAC CE may be used in combination as signaling.

Although this disclosure describes examples of beamformed RS (RS transmission using beams), whether or not a physical signal/channel is beamformed may be transparent to the UE. The beamformed RS and the beamformed signals may be referred to as RS and signals, respectively. Also, the beamformed RS may be referred to as RS resources. Further, beam selection may be referred to as resource selection. Further, the beam index may be referred to as a resource index (indicator) or an antenna port index.

The UE antenna according to one or more embodiments of the present invention may be applied to a UE including a one-dimensional antenna, a planar antenna, and a predetermined three-dimensional antenna.

In one or more embodiments of the present invention, Resource Blocks (RBs) and subcarriers in the present disclosure may be substituted for each other. Subframes, symbols, and slots may be substituted for one another.

The above examples and modified examples may be combined with each other, and various features of these examples may be combined with each other in various combinations. The present invention is not limited to the specific combinations disclosed herein.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate that various other embodiments can be devised which do not depart from the scope of the invention. Accordingly, the scope of the invention should be limited only by the attached claims.

[ description of reference numerals ]

1 radio communication system

10 User Equipment (UE)

101 antenna

102 amplifier

103 circuit

1031 Transceiver (transmitter/receiver)

104 controller

105 application

106 switch

20 Base Station (BS)

2001 baseband precoder

2002 digital-to-analog converter (DAC)

2003 analog precoder (phase and amplitude controller)

201 antenna element group (antenna)

2011 antenna element

202 amplifier

203 transceiver (transmitter/receiver)

204 baseband signal processor

205 call processor

206 transmit path interface

Claims

1. A terminal, comprising:

a receiver configured to receive first information indicating a relationship between an SSB/PBCH (synchronization Signal Block/physical broadcast channel) and an SRS (sounding reference Signal), resource setting of the SRS, and second information associating the first information with the resource setting of the SRS; and

and a processor configured to select a beam used for reception of the SSB/PBCH as a beam used for transmission of the SRS, based on the first information.

2. The terminal of claim 1, wherein,

the processor determines a precoder applied to the SRS based on the SSB/PBCH,

the terminal also includes a transmitter that transmits the SRS precoded using the determined precoder.

3. The terminal of claim 1, wherein,

the receiver receives the first information, the resource setting of the SRS, and the second information using higher layer signaling.

4. A wireless communication method for a terminal, wherein,

receiving first information indicating a relationship between an SSB/PBCH (synchronization Signal Block/physical broadcast channel) and an SRS (sounding reference Signal), resource setting of the SRS, and second information associating the first information with the resource setting of the SRS,

selecting a beam used in the reception of the SSB/PBCH as a beam used in the transmission of the SRS based on the first information.

5. The wireless communication method according to claim 4,

determining a precoder applied to the SRS based on the SSB/PBCH,

transmitting the SRS precoded using the determined precoder.

6. The wireless communication method according to claim 4,

receiving the first information, the resource setting of the SRS, and the second information using higher layer signaling.

7. A base station, comprising:

a transmitter that transmits first information indicating a relationship between an SSB/PBCH (synchronization signal block/physical broadcast channel) and an SRS (sounding reference signal), resource setting of the SRS, and second information associating the first information with the resource setting of the SRS; and

a receiver which receives the SRS transmitted from the terminal,

a beam used in the reception of the SSB/PBCH in the terminal is selected as a beam used in the transmission of the SRS based on the first information.

8. A system comprising a base station and a terminal,

the base station includes:

a transmitter that transmits first information indicating a relationship between an SSB/PBCH (synchronization Signal Block/physical broadcast channel) and an SRS (sounding reference Signal), resource setting of the SRS, and second information associating the first information with the resource setting of the SRS,

the terminal includes:

a receiver configured to receive the first information, the SRS resource setting, and the second information; and

a processor that selects a beam used in reception of the SSB/PBCH as a beam used in transmission of the SRS based on the first information.